Conveyer with displaceable barpulling dog and automatic control therefor



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G. J. KIRCHNER CONVEYER WITH DISPLACEABLE BAR-PULLING DOG AND AUTOMATICCONTROL THEREFOR NR mm m w xmwm Q March 10, 1953 Filed Feb. 15, 1950March 10, 1953 a. J. KIRCH R 2,630,624

CONVEYER WITH DISPLACEA Y BAR-PULLING DOG AND AUTOMATIC CONTROL THEREFORFiled Feb. 15, 1950 3 Sheets-Sheet 2 lqwemi': @fUPG EJ. Hem/v52,

Asmax/ow G. J. KIRCHNER 2,630,624 CONVEYER WITH DISPLACEABLE BAR-PULLINGDOG AND AUTOMATIC CONTROL THEREI' OR 5 Sheets-Sheet 5 1410821607 &950E651 meow/6 fi/Efl/O/WQQ nmzm March 10, 1953 Filed Feb 15 1950Patented Mar. 10, 1953 CONVEYER WITH DIS-PLACEABLE BAR- IULLING DOG ANDAUTOMATIC CON-- TROL THEREFOR George J. Kirchner, Lorain, Ohio, assignorto United States Steel Corporation, a corporation of New JerseyApplication February 15, 1950, Serial No. 144,269

9 Claims.

This invention relates generally to the manufacture of seamless tubesand, in particular, to apparatus for stripping a cylindrical shell froma bar in the manufacture of tubes by the method known as rolling on abar.

The improved method of making seamless tubes by passing a blank onamandrel bar through a rolling mill has recently come into use. Thismethod requires the stripping of the rolled shell from the bar after therolling has been completed. The stripping operation presents quite aproblem because of the size and weight of the bar and shell, thetendency of the shell to adhere to the bar and the fact that the shellis at rolling temperature.

I have invented a novel mechanism for stripping the mandrel bar from arolled shell and automatic control means therefor whereby this operationmay be carried out quickly and effectively. In a preferred embodiment, Iprovide a power-driven chain conveyor having U-shaped traction dogsspaced therealong adapted to engage a pulling head attached to one endof the bar. With this mechanism I pull the bar through a hole in astationary stripper plate too small to admit the shell, thereby holdingthe latter as the bar is pulled out. The dog is pivotally mounted on asaddle carried by the conveyor so as to be displaced by the pulling headas the latter is delivered through the stripper plate after which thedog is restored to position for making tractive engagement with thehead. I also provide means actuated .by the displacement of the dog forautomatically starting the conveyordriv ing motor. After the bar hasbeen entirely removed from the shell, further control means stop theconveyor with the next dog in position to be displaced by the pullinghead on the next bar to be stripped and then tractively to engage it asthe chain is again started.

A complete understanding of the invention may be obtained from thefollowing detailed description and explanation which refer to theaccompanying drawings illustrating a preferred embodiment. In thedrawings,

Figure 1 is a central longitudinal vertical section through the stripperplate and the adjacent end of the chain conveyor, with parts shown inelevation;

Figure 2 is a portion of Figure 1 to enlarged scale, with additionalparts shown in section;

Figure 3 is a transverse section taken on the plane of line III-III ofFigure 2; and

Figure 4 is a circuit diagram of the automatic control system showingcertain mechanical features schematically.

Referring in detail to the drawings, a chain conveyor II] is so disposedas to pull a mandrel bar I I out of a cylindrical shell I2 which hasbeen rolled thereon, while the latter is held stationary by a stripperplate I3 mounted in a supporting standard I4. As clearly shown in Figurel, the plate I3 has a hole therein large enough to admit the bar but notlarge enough to pass the shell. The bar with the shell thereon isadvanced toward the stripper plate and the end of the bar insertedtherethrough by a roller conveyor, one of the rolls of which isindicated at I5.

The conveyor II! as shown in outline in Figure 4 includes a pair ofspaced, parallel traction chains l6 trained over a pair of drivingsprockets I1 and a pair of idler sprockets I8. The two chains areconnected by transverse supporting saddles It spaced at intervalstherealong. These saddles support the bar II when it has been entirelystripped from the shell, as will be explained later. Each pair ofsprockets is mounted on a common shaft, the shaft of the drivingsprockets being driven by a motor I9 through reduction gearing 20.Operation of the motor I9 is under the control of an automatic startingpanel 2|, the details of which are well known, including a start relay22 and a stop relay 23. The latter is controlled by a limit switch 24 ofknown construction operating in timed relation with the travel of theconveyor in a manner to be explained in greater detail later.

Referring now more particularly to Figure l to 3, the chains I55consisting of alternating singlebar links and twin-bar links ride on aplurality of pairs of rollers 25. The rollers are mounted oncross-shafts 26 which are journaled in spaced parallel rails 21. Therails are secured, respectively, to spaced parallel supporting beams 28.Bearing brackets 29 secured to the right-hand ends of these beamssupport the shaft; of the idler sprockets I8 indicated at 30. The lengthof the conveyor is such as to accommodate the full length of the longestmandrel bars in use.

Each mandrel bar I I has a pulling head 3i provided with a shank 32threaded into one end thereof, adapted to receive the tractive forcenecessary to perform the stripping operation. The forward end of thehead tapers to a rounded point. The head has a diameter larger than theshank forming a shoulder 33 at their junc tion. For cooperation with thepulling head, a bifurcated or U-shaped traction dog 34 is pivoted on asaddle or block 35 secured to singlebar links of the chains by screws36. There are two saddles 35 having dogs pivoted thereon uniformlyspaced along the chains. These saddles 3 are generally similar to thoseshown at it As clearly shown in Figures 1 and 2, the dog 34 is shaped toengage the shoulder 33 of the pulling head 31. The forward faces of thesides of the dog are rounded adjacent the top as shown in Figure 2. Thesaddle 35 has spaced upstanding abutments 31 on each side adapted to beengaged by the rear face of the dog when in its upright position, tosustain the reaction resulting from engagement of the dog with thepulling head.

The dog 34 is pivoted on the saddle 35 by means of a through pin 38 andis thereby tiltable from the position shown in solid lines in Figure 2to the position shown in dotted lines. The do has a forwardly projectinglug or toe 39 at the bottom thereof for a purpose which will presentlyappear. A coil spring 40 surrounding the pin as has one end engaging thepin and the other the dog. The pin, furthermore, is secured againstrotation in the saddle. The spring is normally under tension sufiicientto hold the dog in upright position. Down-tilting of the dog increasesthe tension in the spring and the latter, therefore, serves to restorethe dog to upright position as soon as it is released.

A plunger 4! is mounted on a bracket 42 in a position such that it willbe struck by the lug $9 of the dog 34 when the latter is tilteddownwardly. The plunger comprises upper and lower telescoping tubularmembers 43 and 44 having a cap or striker plate 45 and a base 46 securedthereto, respectively. A helical compression spring 4? within the lowertubular member normally supports the upper member in the illustratedposition. A stud 48 extends through the base 44, is secured to thestriker plate 45 and is slidable in a bushing 49 seated in the base 45.A bell crank 58 pivoted to the bottom of the base it is effective onoperation of the plunger 41 to actuate an electric switch 5! through alink 52. The switch 5|, as shown diagrammatically in Figure 3, controlsthe energization of the start relay 22 of the panel 2|.

The operation of the apparatus described above will now be explained onthe assumption that the conveyor I is stopped with the saddle 35 in theposition shown in Figure 2, that the mandrel bar I I with the shell I2thereon has been delivered to the roller conveyor and that the pullinghead 31 on the bar is approaching the stripper plate l3. The conveyor i5is normally driven continuously and immediately advances the pullinghead and leading end of the mandrel bar through the hole in the stripperplate. On continued travel of the mandrel bar after the pulling headpasses through the stripper plate, the tapered end of the head 3| entersthe space between the sides of the dog 34. The dog is then tilteddownwardly to the dotted line position by engagement of the taperedsurface of the head with the inner surfaces of the sides of the dog. Ondown-tilting of the dog, lug 38 operates the plunger 4| thus actuatingswitch 5% which energizes the start relay 22' on panel 2 i.

The motor [9 starts slowly under control of the automatic starting panel2! and drives the sprockets I! in such direction as to move the upperrun of the chains Hi from right to left. In the meantime, the mandrelbar has continued its advance until the head 31 passes sufficientlybeyond the dog 34 to permit it to be restored to vertical position byspring 48. Forward movement of the bar, of course, is eventuallyarrested by engagement of the end of the shell thereon with the stripperplate 13. The chains it continue to travel at slow speed until the dog34 engages the shoulder 33 back of head 3 l, thereby applying tractiveforce to the bar ll tending to strip it from the shell l2. The startingpanel H is preferably arranged to increase the speed of the motor itafter the initial movement of the bar H relative to the shell which, ofcourse, is the moment of maximum load. Continued travel of the chainsentirely withdraws the bar from the shell. As the bar is pulled out, itis supported on the saddles H5 when its trailing end passes beyond thestripper plate.

After the bar H has been pulled entirely out of the shell I2, theconveyor chain continues its travel until the other saddle 35 with thepivoted dog 34 thereon comes into the position shown in Figure 2. Thelimit switch 24 is so adjusted that it closes its contact at this time,completing an energizing circuit for the stop relay 23 on panel board2i, shutting down motor is. The switch 24 may be of any suitable type,e. g., that having a cam driven at a speed proportional to the travelor" the conveyor chain and efiective to'close a contact at predeterminedpoints in the travel. In the meantime, the dog 34 which was operated towithdraw the bar from the shell will have traveled around the drivingsprockets ii and passed out of engagement with the head 3 i. This isfacilitated by the shape of the forward faces of the dog adjacent thetop thereof. Bar I I is thus left on the conveyor 10. On the next cycleof operations, the bar is carried forward by movement of conveyor Iiiand delivered to a roller conveyor (not shown) in alignment therewith.

It will be apparent from the foregoing that the invention provides asimple yet effective means for stripping mandrel bars from tube shellsrolled thereon. The operation of the apparatus is entirely automaticbeing initiated by the advancement of a bar into position for stripping.The tilting dog restores itself to position for tractive engagement withthe head after being temporarily displaced by the advance of the latterand also serves to initiate the starting of the conveyor-driving motorwhich continues thereafter until the second dog is in position to bedisplaced by the next bar preparatory to a succeeding strippingoperation. The axis of a bar being pulled is approximately in thehorizontal plane through the center lines of the chains. Thetractiveeffort exerted by the dog on the pulling head is thereforeapplied thereto substantially along the axis of the bar. There is thusno tendency to transmit any bending stress to the bar which might causebinding of the bar in the shell. In addition, any tendency of the headto jump out of the dog is avoided.

I claim:

1. In an apparatus for stripping a mandrel bar from a tube shellthereon, the combination with a chain conveyor and a motor for drivingsaid conveyor, of a dog pivoted on the conveyor adapted to be displacedby engagement of a bar therewith, means tending to restore the dog tonormal position for tractive engagement with said bar, a switchcontrolling the motor and means actuated by tilting movement of the dogfor operating said switch. I

2. The apparatus defined by claim 1 characterized by said means being adepressible plunger and said dog having a toe engageable with theplunger when the dog is positioned thereabove.

3. The apparatus defined by claim 1 characterized by a limit switchoperated in accordance with travel of the conveyor effective to stopsaid motor when the dog comes into cooperative relation with saidswitch-actuating means.

l. In an apparatus for pulling a mandrel bar from a tube shell thereon,the combination with a chain conveyor and a dog pivoted thereon fortiltin movement to an out-oi-the-way position when struck by a mandrelbar delivered onto the conveyor, means actuated by tilting of the dogefieotive to start the conveyor, and means constantly tending to restoresaid dog to normal position, the dog being shaped to make tractiveengagement with said bar on return to normal position and forwardmovement of the conveyor relative to the bar.

5. The apparatus defined by claim 4 characterized by said dog beingU-shaped and thereby adapted to embrace said bar on return to normalposition after displacement by the bar.

6. The apparatus defined by claim 4 characterized by said conveyorhaving a saddle on which said dog is pivoted, said saddle having anabutment adapted to sustain the reaction on the dog caused by engagementwith said bar.

7. The apparatus defined by claim 6 characterized by said dog beingpivoted on a transverse horizontal axis adjacent the bottom of saidsaddle.

8. The apparatus defined by claim 6 characterized by a pivot pin fixedin said saddle mounting said dog, said restoring means being a helicalspring surrounding the pin and secured to the pin and to the dog.

9. The combination with a conveyor including spaced chains, of a saddleextending therebetween having spaced upstanding abutments thereon, aU-shaped traction dog pivoted on said saddle ahead of said abutments fordown-tilting movement, and means urging said dog to normal positionbearing against said abutments, whereby said dog is adapted to maketractive engagement with a headed bar discharged longitudinally onto theconveyor, after being displaced by the head of the bar and restored tonormal position in which the dog embraces the bar back of the head, saidsaddle having a portion below the level of said chains connecting saidabutments, leaving the space between abutments clear to accommodate thebar, whereby the bar is supported substantially in the plane of thechain for the application of traction.

GEORGE J. KIRCHNER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 462,417 Taylor Nov. 3, 18911,593,501 Martin July 20, 1926 2,047,491 Reiners et a1 July 14, 1936FOREIGN PATENTS Number Country Date 447,333 Great Britain May 15, 1936

